Chironomus annularius sensu Strenzke

Chromosome set of the species is 2n = 8. Chromosomes AB, CD are metacentric, EF—submetacentric and G— telocentric. The species has four NORs: in chromosome arms A, C, E and arm G (Fig.3). Chromosome arm A has an inverted chromosome sequence A2.2. The “basic” sequences are located in the middle of the arm, next to NOR (Fig. 3). All other “basic” sequences are as in C.piger . Species markers are the three BRs located in the shortest chromosome G, one of which is located at the telomere and the other two are after the NOR. The series of dark and light bands between the BR and NOR of the chromosome G is a marker for the species. A high genomic instability was found in the species inhabiting regions highly polluted with heavy metals (Michailova et al. 2018). Seventy-two individuals were studied.

Collection sites: Sofia: South Park, Bezden , Plovdiv: fish pool, Mariza River, Blagoevgrad, Dimitrovgrad, Durankulak, Shable Lake .